|
Posted by Gregsd on May 13, 2005, 12:58 pm
Please log in for more thread options
Group,
Is it possible to calculate the location of points if you know the
straight-line distance between them all? So, A is x from B, B is y
from C, C is w from A and so forth. Given that point A is at 0,0 is it
possible to workout the x,y of all the other points relative to point
A? Any help appreciated.
Greg.
|
|
Posted by ericoneal on May 13, 2005, 8:32 pm
Please log in for more thread options
You may want to look in to Euclidean distance function if you have
arcview spatial analyst or something.
Gregsd wrote:
> Group,
>
> Is it possible to calculate the location of points if you know the
> straight-line distance between them all? So, A is x from B, B is y
> from C, C is w from A and so forth. Given that point A is at 0,0 is
it
> possible to workout the x,y of all the other points relative to point
> A? Any help appreciated.
>
> Greg.
|
|
Posted by willem van deursen on May 13, 2005, 10:14 pm
Please log in for more thread options To be able to do this you need distances AND angle between known and
unknown points, or distances between an unknown point and at least 3
known points. Then it boils down to simple trigonometry.
Your example wont give one answer as long as we don't know the location
of C and some directions, because points at this given distance from
each other can be rotated around A, maintaining the same distance. Also,
these points can be flipped over all axes, still maintaining the same
distance.
A---B
|
|
C
is just as good as
B--A
|
|
C
or
C
|
|
B--A
BUT, this stays relatively simple assuming your area is relatively
small, and you can assume a flat surface. Otherwise, you are dealing
with great circles etc., have a look at
http://williams.best.vwh.net/avform.htm.
Willem
Gregsd wrote:
> Group,
>
> Is it possible to calculate the location of points if you know the
> straight-line distance between them all? So, A is x from B, B is y
> from C, C is w from A and so forth. Given that point A is at 0,0 is it
> possible to workout the x,y of all the other points relative to point
> A? Any help appreciated.
>
> Greg.
>
--
Willem van Deursen, The Netherlands
wvandeursen_nospam@nospam_carthago.nl
replace _nospam@nospam_ for @ to get a valid email address
www.carthago.nl
|
|
Posted by Paul Cooper on May 16, 2005, 9:03 am
Please log in for more thread options wrote:
>Group,
>
>Is it possible to calculate the location of points if you know the
>straight-line distance between them all? So, A is x from B, B is y
>from C, C is w from A and so forth. Given that point A is at 0,0 is it
>possible to workout the x,y of all the other points relative to point
>A? Any help appreciated.
>
>Greg.
And, just to be really picky, what do you mean by a straight line? The
surface of the earth is curved, so a straight line on most map
projections isn't the shortest distance between two points, not
(again, in MOST map projections) is it a line of constant bearing.
Over moderately large distances, the deviation between a straight line
on a map and either of the two possible definitions of a straight line
on the surface of a sphere deviate quite markedly.
Paul
|
| Similar Threads | Posted | | Open source software to calculate travel distances | March 6, 2007, 4:06 pm |
| implicitly calculate a nodes coordinates from edge length | January 29, 2008, 7:21 pm |
| E,N coordinates convert to GB OS National Grid Sheet Coordinates | April 7, 2005, 12:18 am |
| Determining circle distances with varying latitude | April 23, 2006, 7:58 pm |
| A function to calculate distance beetween lat/lon pairs | July 5, 2005, 11:56 am |
| need help: how to calculate volume from classified raster groups | October 17, 2006, 12:56 am |
| Grid Coordinates to UTM | October 14, 2005, 7:20 am |
| Accessing X, Y coordinates | February 18, 2005, 1:48 pm |
| Lat/Long Coordinates?? | March 8, 2005, 12:57 am |
| US-CAN border coordinates | April 26, 2005, 7:07 am |
|
XML Sitemap